A Static Random Access Memory (SRAM) cell may have reduced performance and reliability because of conflicting current flows to a circuit node of the cell (fighting), and unintended alteration of a data stored in the cell (disturb) during read or write operation. Fighting and disturb may have a more frequent and more detrimental effect as operating voltages of the cell are decreased.
Fighting may occur in the cell when, for example, a p-channel Metal Oxide Semiconductor Field Effect Transistor (pMOSFET) configured to operate as a pull-up transistor sources current into a circuit node at a same time that an n-channel MOSFET (nMOSFET) configured to operate as a pass transistor sinks current from the circuit node. Fighting may decrease the reliability of the cell or increase the time needed to perform write operations to the cell.
Disturb may occur in the cell when a word line connected to the cell has a value that selects the cell, in either read operations (read disturb) or write operations (write disturb). Disturb may be a result of a storage node of the cell being coupled to a low or high voltage on a bit line having a capacitance substantially higher than a capacitance of the storage node of the cell.